Solar cells have been developed over half century and are one of the main sources of energy for future alternatives to oil. There are many types of solar cell, such as single crystal silicon solar cells, polycrystalline silicon solar cells, thin film solar cells, organic solar cells, perovskite solar cells, dye sensitization solar cells, and others. Among these solar cells, novel photovoltaic components, such as the perovskite structural material solar cells, have advantages of high power conversion efficiency, low cost, and are easy to manufacture. Although perovskite solar cells using organic material as hole transport layer have excellent efficiency, the organic hole transport layer has a complicated synthesis process and easily reacts with water and oxygen, resulting in poor stability of the photovoltaic devices. In order to improve the stability of perovskite solar cells, inorganic selective contact materials have been developed for the perovskite solar cells.
Deposition of inorganic materials on perovskite layer has improved the device stability. However, there are some disadvantages that prevent its practical use. For example, organic-inorganic hybrid perovskite is susceptible to ion bombardment, and vulnerable to high temperature and polar solvent, causing perovskite decomposition. Further, deposition of inorganic materials usually require high temperature, vacuum sputtering, and other processes in order to form the thin film. Therefore, application of inorganic materials on top of perovskite solar cells is very limited.
However, in order to improve the stability of the perovskite solar cell and to reduce the production cost, a low-cost carbon material has been developed to use as a counter electrode for perovskite solar cell. In addition, due to porosity of counter electrode, light-absorbing materials can be filled in mesoporous scaffold from the top of porous carbon electrode. However, the conductivity of the carbon material is poor. Although a micro-thick porous carbon film can achieve the conductive demand, the main issue is that it is easy to peel off due to poor adhesion, so that it is not easy to maintain the integrity of device architecture when reusing it.
As a result, it is necessary to provide a method of fabricating a solar cell to solve the problems existing in the conventional technologies, as described above.